Multi-Axle EV Drive Control for Axle Load and Traction Balance
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Solution Overview
Problem
In multi-axle-driving electrified vehicles without inter-axle differentials, axle load distribution changes lead to increased energy loss and potential wheel idling, affecting traction and fuel efficiency on irregular surfaces.
Innovation Solution
A drive control device that includes an axle load distribution change control unit and a drive control unit to adjust the driving forces of multiple driving axles based on axle load distribution, using air suspensions and electric motors to manage ground-contact pressure and prevent idling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If axle load distribution is changed to improve traction on irregular surfaces, then ground-contact pressure of wheels increases, but energy loss increases excessively and electric power consumption deteriorates
Solution Approach 1:
The system dynamically adjusts the driving forces of individual electric motors based on real-time axle load distribution. When axle load changes occur, the control unit modifies motor output accordingly, ensuring optimal traction while minimizing energy waste from idle wheel rotation.
Solution Approach 2:
The control unit continuously monitors axle load distribution and uses this feedback to adjust the driving forces of the electric motors. This closed-loop control ensures that driving forces are optimized according to actual load conditions, preventing energy loss from wheel idling while maintaining effective traction.
2Reliability
If axle load distribution is changed to improve traction, then ground-contact pressure increases, but wheel idling occurs at higher rotation speed
Solution Approach 1:
The system dynamically adjusts the driving forces of individual electric motors based on real-time axle load distribution. When axle load changes occur, the control unit modifies motor output accordingly, ensuring optimal traction while minimizing energy waste from idle wheel rotation.
Solution Approach 2:
The control unit changes the operating parameters (driving forces) of the electric motors in response to axle load distribution changes. By adjusting motor torque output according to actual load conditions, the system prevents wheels from idling at high speeds while maintaining necessary traction.
3Device complexity
If independent driving axles are used without inter-axle differential, then vehicle complexity is reduced, but driving forces cannot be adjusted when axle load distribution changes
Solution Approach 1:
The patent replaces the mechanical inter-axle differential system with independent electric motors for each driving axle. This substitution eliminates complex mechanical differentials while enabling electronic control of driving forces, achieving both structural simplification and enhanced adaptability through software-based force distribution.
Solution Approach 2:
The control unit changes the operating parameters (driving forces) of the electric motors in response to axle load distribution changes. By adjusting motor torque output according to actual load conditions, the system prevents wheels from idling at high speeds while maintaining necessary traction.
Data Source
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AI summary
A drive control device for a multi-axle-driving electrified vehicle including a first driving axle that is rotationally driven by a first electric motor and a second driving axle that is rotationally driven by a second electric motor includes: an axle load distribution change control unit configured to perform axle load distribution change control for changing an axle load distribution for the first driving axle and the second driving axle; and a drive control unit configured to control operations of the first electric motor and the second electric motor. The drive control unit is configured to perform driving force change control for changing driving forces of the first electric motor and the second electric motor when the axle load distribution change control unit performs the axle load distribution change control.